Conductive Separator Coating for PSoC Lead-Acid Battery Sulfation
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Solution Overview
Problem
Lead-acid batteries face challenges in maintaining stable cycle characteristics and charge acceptance due to the formation of highly crystalline sulfate salts on electrode surfaces, leading to impaired battery life and water loss, especially when operated in a partial state of charge (PSoC).
Innovation Solution
A method for producing a lead-acid battery separator involves coating a separator substrate with a solution containing a conductive material and a high molecular weight compound, followed by solvent removal, to form a surface layer with uniform electron conductivity, thereby enhancing the separator's performance by preventing sulfation and promoting efficient charge reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engineered carbon materials are coated onto the separator surface to improve charge acceptance and cycle life, then electron conductivity is enhanced, but the coating layer may shed from the separator surface
Solution Approach 1:
The patent uses a composite coating layer comprising engineered carbon materials (for conductivity) combined with a binder material (for adhesion). This composite structure allows the coating to simultaneously achieve electron conductivity and stable bonding to the separator surface, preventing shedding while maintaining the desired electrical properties.
Solution Approach 2:
The binder material acts as an intermediary between the engineered carbon materials and the separator surface. It provides a bonding interface that secures the conductive carbon particles to the separator while maintaining the conductive network, thus preventing layer shedding without compromising electron conductivity.
2Productivity
If a coating layer is formed on the separator surface to promote electrode reaction, then charge acceptance improves, but achieving uniform electron conductivity becomes difficult
Solution Approach 1:
The patent optimizes parameters including the concentration of engineered carbon materials, binder content, coating solution viscosity, and drying conditions to achieve uniform coating deposition. By carefully controlling these parameters, the coating layer forms with consistent thickness and uniform electron conductivity across the separator surface.
Solution Approach 2:
The coating layer is designed to provide localized electron conductivity enhancement at the separator-electrode interface where it is most needed for promoting electrode reactions. The engineered carbon materials are distributed throughout the coating matrix to create conductive pathways precisely where they enhance charge acceptance, while the binder ensures uniform distribution.
3Loss of energy
If the separator is kept in partial state of charge to improve environmental performance, then fuel efficiency improves, but sulfate crystal accumulation impairs charge acceptance
Solution Approach 1:
The patent replaces the chemical mechanism of sulfate crystal formation and accumulation with a physical-electrical mechanism. The engineered carbon coating provides alternative electron conduction pathways that facilitate charge transfer without requiring sulfate dissolution, thereby maintaining charge acceptance even when sulfate crystals are present on the electrode surfaces during PSoC operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in a lead-acid battery separator with improved cycle characteristics and charge acceptance, inhibiting sulfation and reducing water loss, thus extending battery life and maintaining performance over a fixed cycle.
Implementation Method 1
the high molecular weight compound has a viscosity of 3000 mPa·s to 10,000 mPa·s at 20° C. when dissolved at 1 weight % with respect to a solvent in which the high molecular weight compound is soluble
Implementation Method 2
a solvent removal step in which the solvent is removed from the coating solution that has been coated onto the separator substrate in the coating step
Data Source
AI summary
The present invention provides a method for producing a separator for lead acid storage batteries, said method comprising a surface layer formation step which includes: a coating liquid preparation step wherein a coating liquid that contains a solvent, a conductive material and a high-molecular-weight compound is prepared; a coating step wherein the coating liquid obtained in the coating liquid preparation step is applied to at least one surface of a separator base material; and a solvent removal step wherein the solvent is removed from the coating liquid that has been applied to the separator base material in the coating step. With respect to this method for producing a separator for lead acid storage batteries, the high-molecular-weight compound is contained in an amount of from 0.1% by mass to 25% by mass relative to the solid content of the coating liquid.